School of Molecular Biosciences, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, U.K.
Ubiquigent Ltd, Dundee University Incubator, James Lindsay Place, Dundee DD1 5JJ, U.K.
J Med Chem. 2024 Sep 12;67(17):15557-15568. doi: 10.1021/acs.jmedchem.4c01184. Epub 2024 Aug 27.
DNA damage triggers cell signaling cascades that mediate repair. This signaling is frequently dysregulated in cancers. The proteins that mediate this signaling are potential targets for therapeutic intervention. Ubiquitin-specific protease 1 (USP1) is one such target, with small-molecule inhibitors already in clinical trials. Here, we use biochemical assays and cryo-electron microscopy (cryo-EM) to study the clinical USP1 inhibitor, KSQ-4279 (RO7623066), and compare this to the well-established tool compound, ML323. We find that KSQ-4279 binds to the same cryptic site of USP1 as ML323 but disrupts the protein structure in subtly different ways. Inhibitor binding drives a substantial increase in thermal stability of USP1, which may be mediated through the inhibitors filling a hydrophobic tunnel-like pocket in USP1. Our results contribute to the understanding of the mechanism of action of USP1 inhibitors at the molecular level.
DNA 损伤会触发细胞信号级联反应，从而介导修复。这种信号传导在癌症中经常失调。介导这种信号传导的蛋白质是治疗干预的潜在靶点。泛素特异性蛋白酶 1（USP1）就是这样的一个靶点，已经有小分子抑制剂在临床试验中。在这里，我们使用生化分析和冷冻电子显微镜（cryo-EM）来研究临床 USP1 抑制剂 KSQ-4279（RO7623066），并将其与成熟的工具化合物 ML323 进行比较。我们发现 KSQ-4279 与 ML323 结合在 USP1 的相同隐匿位点，但以略有不同的方式破坏蛋白质结构。抑制剂结合会导致 USP1 的热稳定性显著增加，这可能是通过抑制剂填充 USP1 中的疏水隧道样口袋来介导的。我们的研究结果有助于从分子水平上理解 USP1 抑制剂的作用机制。
